Figure 2. ST3GalI interacts with EGFR signaling pathway in ovarian cancer.

(A) The correlation of 20 STs and significant cell receptors in the ES2ovarian cancer cell line were analyzed by the L1000 mRNA microarray. Data shown are mean ± SD of separate repeat experiments. (B) The analysis of mRNA expression of ST3GalI and EGFR from Oncomine TCGA (n=562), Bittner (n=241), and Lu (n=50) ovarian cancer genomics is shown. The expression of EGFR was compared between low and high ST3GalI groups using a tercile approach. (C) The mRNA expression of α2,3-sialyltransferases and TKI drug efficiency (Actarea) are shown from the CCLE ovarian cancer dataset. (D-E) Western blot analysis of EGFR and phospho-EGFR in ST3GalI knocked-down or overexpressing cells compared to controls is shown. GAPDH was used as control (same GAPDH as in Figure 1D-1E). (F) The co-immunoprecipitation assay coupled with immunoblotting analysis to evaluate the protein-protein interaction of ST3GalI and EGFR is shown. (G) Immunoblotting of ST3Ga1I immunoprecipitated with anti-EGFR antibodies in SC and ST3GalI knock-down of ES2 cell line are shown. (H) Time course RNA and protein analysis showing EGFR expression during ST3GalI knock-down.